This invention relates to ignition systems for internal combustion engines and more particularly relates to an electronic ignition system utilizing a pair of magnetic pick-ups wherein utilization of the pick-ups for ignition firing is selectively controlled.
The present invention is directed toward an improved ignition system wherein automatic transfer is provided between a pair of magnetic pick-ups. One of the pick-ups, referred to as the start pick-up, normally controls ignition firing when the engine is being cranked. When the engine comes under its own power, control automatically transfers to the run pick-up so that the latter controls ignition firing while the engine is running. Should a condition occur indicative of lack of signals from the run pick-up above a predetermined minimum frequency, then control of ignition firing transfers back to the start pick-up. An important benefit of the invention is that should a failure occur in the run pick-up and/or associated circuitry, the ignition system can continue to operate from the start pick-up. The system is especially useful in conjunction with an electronic spark timing controller.
Additional features of the invention will be seen in the ensuing description and claims which are to be considered in conjunction with the accompanying drawings illustrating a preferred embodiment of the present invention according to the best mode presently contemplated in carrying out the invention.